As treatments for a stenosed site or an occluded site appearing inside a lumen such as blood vessels, urethras, and the like, a treatment is known in which a balloon is pressed against an inner wall inside the lumen such as urethras and the like. Japanese Application Publication No. 2001-198222 discloses a balloon which is used for pressure hemostasis performed on bleeding from a prostatic urethra after transurethral prostatectomy is performed in order to treat benign prostatic hyperplasia.